The outline, objectives and methods to be used in this proposed project are the same as those that have been employed in the project HE03130 which is now in its 17th year. Although substantial advances have been made (the progress Report) in the last two years the main ojectives and plans of the proposed research remain the same. The aim of the proposed work is to study the interrelationship of metabolic regulation and organ function in in vivo situations both under control and stressful conditions. A continued study of the turnover and oxidation of the major metabolic substrates (FFA, TG, glucose, lactate, ketone bodies) will be undertaken in an effort a) to characterize the diurnal variations in metabolic control mechanisms, b) to correlate organ function with the utilization of various metabolites for optimal cellular economy (mostly in the heart, but also in other organs), c) to compare and contrast metabolic changes in the myocardium during infarction (produced by various experimental means), local and generalized hypoxia, various forms of experimental shock (hemorrhagic, endotoxic, anaphylactic and drug-induced), and d) to make similar comparisons with regard to the metabolism of other vital organs, i.e., skeletal muscle, brain, liver, intestine, kidney and adipose tissue.